3 files changed, 54 insertions, 12 deletions

diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 8447c31e27f2..f5a2d445d0c0 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -18,13 +18,15 @@
 #include <asm/unaligned.h>
 #include <linux/iio/common/st_sensors.h>
 
+#include "st_sensors_core.h"
+
 static inline u32 st_sensors_get_unaligned_le24(const u8 *p)
 {
 	return (s32)((p[0] | p[1] << 8 | p[2] << 16) << 8) >> 8;
 }
 
-static int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
-						u8 reg_addr, u8 mask, u8 data)
+int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
+				    u8 reg_addr, u8 mask, u8 data)
 {
 	int err;
 	u8 new_data;
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.h b/drivers/iio/common/st_sensors/st_sensors_core.h
new file mode 100644
index 000000000000..cd88098ff6f1
--- /dev/null
+++ b/drivers/iio/common/st_sensors/st_sensors_core.h
@@ -0,0 +1,8 @@
+/*
+ * Local functions in the ST Sensors core
+ */
+#ifndef __ST_SENSORS_CORE_H
+#define __ST_SENSORS_CORE_H
+int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
+				    u8 reg_addr, u8 mask, u8 data);
+#endif
diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c
index 3e907040c2c7..6a8c98327945 100644
--- a/drivers/iio/common/st_sensors/st_sensors_trigger.c
+++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c
@@ -14,32 +14,65 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/trigger.h>
 #include <linux/interrupt.h>
-
 #include <linux/iio/common/st_sensors.h>
-
+#include "st_sensors_core.h"
 
 int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
 				const struct iio_trigger_ops *trigger_ops)
 {
-	int err;
+	int err, irq;
 	struct st_sensor_data *sdata = iio_priv(indio_dev);
+	unsigned long irq_trig;
 
 	sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
 	if (sdata->trig == NULL) {
-		err = -ENOMEM;
 		dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
-		goto iio_trigger_alloc_error;
+		return -ENOMEM;
 	}
 
-	err = request_threaded_irq(sdata->get_irq_data_ready(indio_dev),
+	irq = sdata->get_irq_data_ready(indio_dev);
+	irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
+	/*
+	 * If the IRQ is triggered on falling edge, we need to mark the
+	 * interrupt as active low, if the hardware supports this.
+	 */
+	if (irq_trig == IRQF_TRIGGER_FALLING) {
+		if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
+			dev_err(&indio_dev->dev,
+				"falling edge specified for IRQ but hardware "
+				"only support rising edge, will request "
+				"rising edge\n");
+			irq_trig = IRQF_TRIGGER_RISING;
+		} else {
+			/* Set up INT active low i.e. falling edge */
+			err = st_sensors_write_data_with_mask(indio_dev,
+				sdata->sensor_settings->drdy_irq.addr_ihl,
+				sdata->sensor_settings->drdy_irq.mask_ihl, 1);
+			if (err < 0)
+				goto iio_trigger_free;
+			dev_info(&indio_dev->dev,
+				 "interrupts on the falling edge\n");
+		}
+	} else if (irq_trig == IRQF_TRIGGER_RISING) {
+		dev_info(&indio_dev->dev,
+			 "interrupts on the rising edge\n");
+
+	} else {
+		dev_err(&indio_dev->dev,
+		"unsupported IRQ trigger specified (%lx), only "
+			"rising and falling edges supported, enforce "
+			"rising edge\n", irq_trig);
+		irq_trig = IRQF_TRIGGER_RISING;
+	}
+	err = request_threaded_irq(irq,
 			iio_trigger_generic_data_rdy_poll,
 			NULL,
-			IRQF_TRIGGER_RISING,
+			irq_trig,
 			sdata->trig->name,
 			sdata->trig);
 	if (err) {
 		dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
-		goto request_irq_error;
+		goto iio_trigger_free;
 	}
 
 	iio_trigger_set_drvdata(sdata->trig, indio_dev);
@@ -57,9 +90,8 @@ int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
 
 iio_trigger_register_error:
 	free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
-request_irq_error:
+iio_trigger_free:
 	iio_trigger_free(sdata->trig);
-iio_trigger_alloc_error:
 	return err;
 }
 EXPORT_SYMBOL(st_sensors_allocate_trigger);